Wireless telecommunications are deeply integrated in today's lifestyle. The selection of tools, functionalities and units relying on wireless telecommunications is constantly widening, and requirements on wireless telecommunications is consistently increasing. In addition to the increase of requirements, prices of such units are dropping because of high demand, and fierce competition, making it essential for manufacturers to develop new technology manufacturable at lower costs.
In personal wireless units, most of the improvements to support more complex applications or functionalities have been invested in the elaboration of stronger encoding/decoding techniques. Such encoding/decoding techniques have proven to improve performances of wireless units, but however require more elaborate Digital Signal Processors, which in turn result in more expensive wireless units, and greater energy consumption.
An other alternative relies on multiple inputs multiple outputs (MIMO) communication systems. MIMO systems use multiple transmit and receive antennas to increase capacity in rich multipath channels. However, works on MIMO channel capacity have established the dependence of the system capacity on the statistical properties of the complex transfer matrix describing the MIMO channel, where this transfer matrix depends on both the propagation environment and the antenna configurations.
Efforts have also been invested on improving antennas used in such wireless units. To improve performances, many units rely on antennas composed of multiple elements, generating discrete radiation patterns. Although such antennas have provided noticeable improvements, such antennas have also demonstrated limited capabilities in harsh environments (i.e. slow fading, correlated MIMO channels), can not be dynamically adapted to a wide variety of wireless environments, and increase the size and cost of wireless units.
Thus, such limitations in current antennas and antenna systems force designers of wireless units to develop and rely on ever more complicated and sophisticated encoding schemes and algorithms to improve performances. There is therefore a need for an antenna and an antenna system which alleviates some of the problems encountered in today's antennas and antenna systems.